In case you were wondering (because I was), SPI stands for the Society of the Plastics Industry, Inc. These guys came up with the resin identification code (in 1988, a great year)! I have been wondering about this ever since I got interested in plastics and finally found an answer. You might have seen these numbers (ID codes) affixed to all of your soda/milk/laundry detergent bottles as well as Nalgenes, car parts, cosmetic cases…I could go on for forever.

Anyway, the focus of my paper is the recycling aspect and as part of my project, I want to have a section describing the history of recycling. In order to talk about the plastics and how they are recycled, I first need to know what each is made up of. So, to keep it straight in my head (because I’m constantly mixing up 3 and 6…) I’m going to make a list! The SPI site also had free PDF downloads of the resin ID code images (all 7 of them) which I thought was pretty cool. If I ever feel the urge to print out a bunch of #7s (and produce more waste), I’ll have the official image…

Here’s the list, along with some tidbits about why they’re so darned GREAT.

#1: Polyethylene Terephthalate – PET or PETE. Most commonly used to bottle carbonated beverages but can also house water, sport drinks (seeing a pattern here?), salad dressing, peanut butter jars and oven-ready pre-packaged food (yum). The reason this plastic is so ubiquitous is because it’s clear (aesthetics, consumers can see what they’re buying), it resists heat (according to the SPI website…I’m not buying that) and it acts as a barrier to gas, which means it won’t explode when filled with bubbly soda.

#2: High Density Polyethylene – HDPE. Most commonly  used in milk and laundry detergent bottles as well as yogurt cups and cereal box liners. Used because the chemical makeup allows it to be pliable but durable, it resists moisture and is easily formed and processed.

Here’s where it gets tricky…

#3: Polyvinyl Chloride – PVC. Used in food packaging! Also a component in construction projects (piping, window frames, floor tiles) and found in wire insulation. PVC is used because it is extremely durable, resists grease, oil and other chemicals (impermeable) and it is easy to blend (note: not sure what this means yet, but I’ll find out).

#4: Low Density Polyethylene – LDPE. Used as a plastic film because of its extreme flexibility and toughness, and is used to make lids for bottles. Used for frozen food bags, bread bags and squeezable bottles (think condiments).

#5: Polypropylene – PP. Found in ketchup bottles and yogurt cups and large, molded car parts. This plastic has a high melting point, meaning it is suitable for applications where heat is a factor (hence car parts).

#6: Polystyrene – PS. Versatile (how descriptive…). You may recognize this plastic the next time you pick up a CD, because PS is what makes up that jewel case of yours. Also found in grocery store meat trays, hard-plastic drink-ware and is a major component of summer-time picnics. You may be thinking “but meat trays and plastic cups don’t look anything alike!” Let’s get back to that versatile bit. Polystyrene can be produced as a rigid plastic or “foamed” (meat trays, styroFOAM)…this is something I’m still getting over and still puzzled about. But never fear, I will come up with an answer!

and last but certainly not least….the name sake of this very blog! #7! No complicated chemistry jargon in the name, this plastic is simply known as “other.” Descriptive, right? Well, SPI had to come up with something for the rest of the plastic stuff…anyway, there are two reasons this plastic is classified as such: 1) It it is composed of plastics other than #s 1-6 OR 2) it is made up of a combo of #s 1-6 in a “multilayered combination” (sort of like a cake). You’ll find #7 in reusable water bottles (anybody holding onto a Nalgene?) and the big water-cooler bottles the office-folk like to crowd around. This plastic is used in long-term applications and as such, is harder to recycle…and theoretically if it’s not getting recycled, it’s getting thrown away, and could be getting into the ocean…hence “sevenintheocean.” The connection has been made!

What I also found interesting on SPI’s website was that it noted that most of the plastics we are allowed to recycle are numbers 1 and 2 (these two categories represent 96% of all plastic bottles and containers used in the US) and that this is ok. The justification here is that since we mostly just consume plastics 1 and 2, it’s ok that we can’t recycle 5 and 6 right now. I’m sorry, but no, that is not OK.

I think that’s enough shouting about plastic for the night.  You can start to see why plastic recycling isn’t as straightforward as it seems! There is a lot of room for ambiguity, consumers get confused over which number is what and unfortunately, most recycling facilities aren’t equipped with machinery to process plastic films and used food/beverage containers. More research to be done!

Conclusion: become aware of what you purchase. The plastics industry doesn’t want you to know which plastics you’re consuming, that’s why they put the numbers on the bottom of containers! Go into the store sometime and see how many items you can pick up not wrapped, packaged or bottled in plastic. It is frustrating.


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